I searches the archives but didn't see this particular topic.
67 3-synchro o/d
Hooked up the od wiring today and test drove. No od engagement. I have current to the solenoid, temporarily bypassed the vacuum switch, but no od at speed.
Got underneath and with it in 4th gear ignition on had my wife flick the switch. Test light shows the current hitting the solenoid and I can hear it click but when the switch is put back to "normal" the light does not go out and there is no sound from the solenoid. Turn off the key, turn it back on and the light is out til the switch is hit then the light and sound from the solenoid again.
questions: does the solenoid stay engaged even when od switch is turned off?
does the power stay supplied to the solenoid with the switch off?
how much does the rpm drop when od is engaged?
should I be able to hear the rpm drop? ( no tach yet)
how touchy are these things? i have zero experience with this.
overdrive questions
The MG Experience ~ MGB & GT Forum ~ Archives
MG MGB and MGB GT Tech Talk
If you would like to post a reply, please click below to visit the The MG Experience Forums:
MGB & GT Forum: overdrive questions
http://www.mgexperience.net/phorum/read.php?1,569022
Join the discussion, post your photos, or ask your own questions. Membership is FREE!
MGB & GT Forum: overdrive questions
http://www.mgexperience.net/phorum/read.php?1,569022
Join the discussion, post your photos, or ask your own questions. Membership is FREE!
May 28, 2007 13:30:37
May 28, 2007 13:53:53
Not sure about the electrics, but you will definitely feel it engage on the road The rpm drop is something like 500 - 700 rpm at road speed. The difference is very much like going from 4th to 5th on a conventional 5 speed transmission. Assuming that the OD is in good condition and its electrics are all OK, then they are reliable and durable. FB
May 28, 2007 20:28:22
No answers but don't leave the od engaged and shift into reverse. If the switch fails, you will cause massive cash loss.
May 28, 2007 20:37:24
Type D overdrive.? Its been a while for me. Have you changed the filter, Id try some automatic transmission fluid in it between oil changes if it were mine. It will not hurt if you just leave in in for good.
May 29, 2007 14:05:25
chuckw2 Wrote:
Quote: "
temporarily bypassed the vacuum switch, but no od at speed...
... but when the switch is put back to "normal" the light does not go out and there is no sound from the solenoid. Turn off the key, turn it back on and the light is out til the switch is hit then the light and sound from the solenoid again.
questions: does the solenoid stay engaged even when od switch is turned off?
does the power stay supplied to the solenoid with the switch off?
"
temporarily bypassed the vacuum switch, but no od at speed...
... but when the switch is put back to "normal" the light does not go out and there is no sound from the solenoid. Turn off the key, turn it back on and the light is out til the switch is hit then the light and sound from the solenoid again.
questions: does the solenoid stay engaged even when od switch is turned off?
does the power stay supplied to the solenoid with the switch off?
"
Hello, DO NOT bypass the vacuum switch, simply disconnect it. This device is set to keep the overdrive engaged when engine is rev. at high speed, and prevent the driver from increasing even more the engine speed by 700 rpm while already at 5000 +.
The vacuum switch was discontinued on later models. I disconnected permanently the one on my 67 B GT (but remember to slow the car prior to turn off the OD). If you do the same your solenoid will disengage correctly.
Sorry I don't know why your overdrive does not engage at speed but i would suggest you check your connection under the car (it should be a yellow wire) maybe wind in the tunnel while driving make the connection to fail. Sometimes some oil from the gearbox vent spreads on it making the connection fail and resume again and again at a machine gun speed !
Hope this will help
May 30, 2007 07:51:59
mg4sale Wrote:
Quote: "
chuckw2 Wrote:Quote:
temporarily bypassed the vacuum switch, but no od at speed...
... but when the switch is put back to "normal" the light does not go out and there is no sound from the solenoid. Turn off the key, turn it back on and the light is out til the switch is hit then the light and sound from the solenoid again.
questions: does the solenoid stay engaged even when od switch is turned off?
does the power stay supplied to the solenoid with the switch off?
Hello, DO NOT bypass the vacuum switch, simply disconnect it. This device is set to keep the overdrive engaged when engine is rev. at high speed, and prevent the driver from increasing even more the engine speed by 700 rpm while already at 5000 +.
The vacuum switch was discontinued on later models. I disconnected permanently the one on my 67 B GT (but remember to slow the car prior to turn off the OD). If you do the same your solenoid will disengage correctly.
Sorry I don't know why your overdrive does not engage at speed but i would suggest you check your connection under the car (it should be a yellow wire) maybe wind in the tunnel while driving make the connection to fail. Sometimes some oil from the gearbox vent spreads on it making the connection fail and resume again and again at a machine gun speed !
Hope this will help
"
chuckw2 Wrote:Quote:
temporarily bypassed the vacuum switch, but no od at speed...
... but when the switch is put back to "normal" the light does not go out and there is no sound from the solenoid. Turn off the key, turn it back on and the light is out til the switch is hit then the light and sound from the solenoid again.
questions: does the solenoid stay engaged even when od switch is turned off?
does the power stay supplied to the solenoid with the switch off?
Hello, DO NOT bypass the vacuum switch, simply disconnect it. This device is set to keep the overdrive engaged when engine is rev. at high speed, and prevent the driver from increasing even more the engine speed by 700 rpm while already at 5000 +.
The vacuum switch was discontinued on later models. I disconnected permanently the one on my 67 B GT (but remember to slow the car prior to turn off the OD). If you do the same your solenoid will disengage correctly.
Sorry I don't know why your overdrive does not engage at speed but i would suggest you check your connection under the car (it should be a yellow wire) maybe wind in the tunnel while driving make the connection to fail. Sometimes some oil from the gearbox vent spreads on it making the connection fail and resume again and again at a machine gun speed !
Hope this will help
"
I will try this-thanks!
Custom Search
This is an archived discussion from the The MG Experience Forums
If you would like to post a reply, please click below to visit the The MG Experience Forums:MGB & GT Forum: overdrive questions
Archive Index | The MG Experience Forums | Return to The MG Experience